Blasting cartridge



'March 17; 1936-* D. FERRELIT Er AYL- Y2,034,569

'l LAsTING CARTRIDGE Filed oct. 18,*1935 THE/R Hr ron V the escape `Jof flames,or noxious v2o. Figairanemargel 130 therefor in the body of coal or other material2 Pri-rented 17, 193e 4 uNlTlezo STATES Dent This invention relates to blasting cartridges. It has for its principal objects to provides selfcontained blasting cartridge which will increase the' eilectiveness of the blast, which will prevent gases from thef (cartridge: which will facilitate assembly and disassembly Vof theparts; and which will ybe of simple and'economical construction and of comlJact design. The invention consists in the blasting cartridge and in the parts and combinations and arrangements of .parts hereinafter described 4and claimed. In thel accompanying drawing, which forms part of this speciiication and wherein like symbols refer to like parts wherever they occur,

Fig. 1 is a vertical section through a body to M be blasted, showing in side elevation a blasting cartridge embodying our invention mounted' in .a blast hole provided therefor in said body,-

tion through said blasting cartridge,

Fig. 3 is a view similar to Fig. 1 showing inV central longitudinal section a modifled form of blasting cartridge: andY I.ig..4-is` a view similar to Fig. 3 showing another modii'led form of blasting cartridge.

Referring to Fig. 1 ofthe accompanying drawing, a blasting cartridge A embodying our invention is mounted in a blast hole I provided to be blasted and :the hole is closed by suitable stemming l. As shownin Fig. 2, the blasting cartridge A comprises separable hollow cylindrical sections I and 5 that are'detachably connected together'by a threaded leak proof joint 5. The cartridge is provided with end chambers 1, adapted to be lled with a suitable blasting fluid, l and an intermediate chamber' adapted to contain an explosive or other expanding agent 9.

40 adapted to. be red by an electric current conducted threto through wires I0. The end and intermediate chambers are separated by iluid tight partitions in the form of pistons II that are slidable in the end chambers 1. Suitable stop rings or shoulders I2 are located inside the cartridge for limiting the sliding movement of `the pistons in -the end chambers 1. Rubber butler or cushioning rings I3 are mounted against the pis- -ton' oppomng facesof the stop rings I2 to cushion the'force of the' pistons II. 'I'he open ends of:

the cartridgeconstitute vent openings at the outerendsof the respective end chambers 1. 'I11e vent opening in section 4.V of the cartridge is tem- Aporarlly closedgby a wooden 'plug I4; and the ventopening in the other cartridge sectionA icentral longitudinal secl l:trasmite QABTRIDGE Carterville, and Helmholtz, Harrisburg, lll

Application october 1s, 193s, serial No. 694,026

Arthur w.

is closed by a rupturable disk I 5 of metal or other suitable material, which is clamped between the outer face of the adjacent piston stop 8 and a ring n'ut I6 threaded. into said opening.v The rupturable disk I5 is made of material adapted `5 to rupture at a pressure that is considerably less 4than would be required to rupture the other walls of the cartridge. 'I'he end chambers may be providedwith side vent openings that are temporarily closed by means of wooden plugs I1.

In the use of the above blasting-cartridge, the two sections l and 5 thereof are separated. the explosive 9 is inserted in the opening in the inner end of one of said sections and the ri'ng wires I0 connected to said explosive. The two l5 cartridge sections 4 and-5 are then screwed'together and the pistons I I are then slid inwardly in the respective end chambers 1 in abutting re-V lation to the stopsA I2 at the inner ends thereof. 'I'he cartridge chambers 1 are thenv filled with any suitable blasting iiuid, such as water, gas or air.v either under pressure or without pressure, orl a thin liquid of mud and water or mud, water and air, is then poured-intok each end chamber 1 to substantially lill the same and the vent open- 25 ings in -said chambers are then closed by means of the closure members I 4, I5 and I1. The loaded cartridge is then placed in the blastlhole I, i'n the coalbody 2, the hole closed by the stemming 3 and an )electric current passed through 301 andl l1 to open and the fluid to be discharged 440l through the vent openings closed thereby at a velocity andpressure high enough to break up a large mass of the surrounding coal body 2. After the blast, the cartridge may be recovered and again used by vent v 'I'hemodiedcartridgeshown in Fig. 3 is also -providedwith endA and intermediate chambers I8 and I9, respectively. The intermediate chamber n is provided with-a1 suitable explosive '2d 50i 'adapted to be exploded by an electric current". supplied thereto throughsuitable wires' 2I; and the end chambers I8 are providedwith pistons 22 and-23, respectively. The piston 22.in one endchamber has a conical outer endfportion 24,55

reloading 'and replacing lthe 45'A A Y I adapted to close an opening provided therefor in a rupturable sealing member that coversthe vent opening at the outer end of "said chamber and is held in place by means of a threaded clamping ring 26. The piston 23 in the other end chamber has its outer end portion 21 vshaped after the manner of a truncated cone; and the vent opening in the outer end of said chamber is sealed by means of a rupturable disk 28 that is held in place by means of a threaded retaining ring 29. If desired, the pistons 22 and 23 may be prevented from leaving the chambers in which they work by means of pins 30 and 3|, respectively, which are fixed to the walls of said chambers and seat within longitudinal grooves pro-v vided therefor in said pistons. A suitable pipe line 32 leads to the chamber containing the piston 23 for supplying fluid under pressure to the space between the outer ends of said chamber and piston.

With the blasting cartridge shown in Fig. 3, it is preferable to place the coal body in a state of strain, prior to the main blast, by forcing into it a iiuid, gas or mud stream under sufcient pressure to set up the desired strain. The pressure building medium is applied to the body through a pipe 32a leading to the blast hole and lls upA all iissures and cracks in the vicinity thereof, and thereby builds up a strain that greatly increases vthe eiectiveness of the blast produced by the blasting cartridge. The pressure building medium may or may not be under pressure and may be supplied by a separate hole or holes in coal body. With this form of cartridge, the pistons are forced outwardly at a high velocity by the explosion of the explosive charge and rupture the seals at the ends of the cartridge. The piston 23 having the blunt end of relatively small area is forced into the static medium surrounding thev cartridge, resulting in a high pressure wave which causes an initial fracture of the coal body. The piston 22 in its outward movement compresses the uidin its chamber to a higher pressure sufficient to rupture the vent closure and discharge said fluid from said chamber into the static medium surrounding the cartridge, thereby imparting a ten'iiic shock or impulse to the medium which causes a general fracture or breaking down of the coal body. v

The modiiied cartridge C shown in Fig. 4 is 'provided with a chamber 33 adapted to receive explosivecharge 34 and a chamber 35 adapted to receive the blasting uid. The chambers 33 and 35 are separated by a piston 36 working between cushioned stops 31 provided therefor in they chamber for the blasting uid. The outer end of the explosion chamber 33 is closed by means* of a threaded cap 38. The outer -end of the chamber 35 for the blasting fluid is closed by a rupturable disk 39, which is clamped between the knife edge of a ring seated against a shoulder provided therefor in said chamber, and a ri'fg nut 4|, which is threaded into the opening closed by the disk and forms a die against which theseal is ruptured. The explosive in the explosion chamber is exploded by an electric current supplied thereto through wiresl 42 leading into said chamber; and the blasting fluid is supplied to the chamber through a pipe line 43 leading thereto. With this form of cartridge, the

expanding gases resulting from the explosion of resulting from the explosion of the explosive charge from escaping into the mine.

It isj'evident that numerous changes may be made without departing from our invention and we do not wish to be limited to the precise arrangements shown and described.

What we claim is:

1. A blasting cartridge comprising a casing having two pistons slidable therein, rupturable sealing for closing the ends of said casing,

and an explosive charge in said casing between said pistons. one of said pistons having a conical end portion adapted to seat within an opening provided therefor in the rupturable disk adjacent thereto.

2. A blasting .cartridge comprising a casing having two pistons slidable therein, rupturable sealing disks for closing the ends of said casing, and an explosive charge in said casing between Y said pistons, one of said pistons having a truncated conical end portion adapted to engage the rupturable disk adjacent thereto.

3. lA blasting cartridge comprising a casing having two pistons slidable therein, rupturable sealing disks for closing the ends of said casing, an explosive charge in said casing ybetween said pistons, one of said pistons having a truncated conical end portion adapted to engage the rupturable disk adjacent thereto, and means for supplying a blasting uid to the space between said last mentioned piston and said disk.

4. A blasting cartridge comprising a casing having two pistons slidable therein, rupturable sealing disks for closing the ends of said casing, an explosive charge in said casing between said pistons, one of said pistons having a truncated conical end portion adapted to engage the rupturable disk adjacent thereto, means for supplying a blasting fluid to the space between said last mentioned piston andsaid disk, and means for limiting the outward travel of said pistons.

5. A blasting cartridge comprising a casing having two pistons slidable therein, rupturable sealing disks forclosing the ends of said casing,

and an explosive charge in said ycasing between said pistons,said casing being made of separable sections whereby access may be had to said casing to enable the explosive charge to be placed therein.

6. A blasting cartridge comprising a casing having a piston slidable therein, an explosive Acharge in one end of said casing, a removable cap for said end of said casing, a rupturable sealing disk in the other end of said casing, a ring seated in said casing orthe inner side of said disk and having a knife edge in engagement therewith, and

a ring threaded into said casing in abutting relation to the outer side of said disk.

DENT FERRELL.

ARTHUR W. I IELMHOL'IZ. 

